Events by month

Ian Payne, Department of Pure Mathematics University of Waterloo

“Continuation of Discrete Homotopy”

I will continue to prove that the operation I defined last week is well defined, and is a group operation. The next step is to define higher homotopy groups, and maybe even do a (very) small example.

Mehdi Radjabalipour, Iranian Academy of Sciences

“Algebraic frames”

Graham Denham, Western University

“Duality properties for abelian covers”

Mehdi Monfared, University of Windsor

“Involutions and Trivolutions on Second Dual Algebras”

Dima Sinapova, University of Illinois, Chicago

"Powers of singular cardinals"

Peter Sinclair, University of Waterloo

"Auxiliary Results on Homotopy Groups and Digraphs"

Abstract: Two weeks ago, we defined a digraph $F^k(X,x_0)$, whose vertices were a particular set of homomorphisms, and a group $\sigma_k(X,x_0)$, whose elements were connected components of $F^k(X,x_0)$. This week, we will begin looking at these structures in more detail.

Nico Spronk, Department of Pure Mathematics, University of Waterloo

"On the subalgebra of a Fourier-Stieltjes algebra generated by pure positive definite functions"

Please note the time

David Lippel, Haverford College

“Reverse VC calculations”

Jessie Yang, McMaster University

Tropical Severi Varieties”

Carrie Knoll, Department of Pure Mathematics,  University of Waterloo

“Idempotent operations in reflexive digraphs”

Timothy Caley, Department of Pure Mathematics, University of Waterloo

"A new algorithm for the Prouhet-Tarry-Escott problem"

Kai-Cheong Chan, University of Waterloo

“On tensor products of digraph algebras over pre-ordered groups ”

Jeffrey Shallit, School of Computer Science, University of Waterloo

"Rational numbers and automata"

In this talk, I will describe a new model for describing certain sets S of rational numbers using finite automata. We will see that it is decidable if every element of S is an integer, and that sup S is computable. However, closely related questions are still open. There are applications to combinatorics on words.

Refreshments will be served in MC 5046 at 3:30pm. All are welcome.

Cassie Naymie, Pure Mathematics, University of Waterloo

“Roth’s theorem on finite abelian groups”

Ross Willard, Pure Mathematics, University of Waterloo

"Larose's theorem"

Putting together some of the machinery developed this term, I will prove Larose’s Theorem: if X is a finite, connected reflexive digraph and X admits a Taylor operation, then for every k ≥ 1, the k-th homotopy group of X is trivial.

Jerry Wang, Harvard University

"Pencils of quadrics and 2-Selmer groups of Jacobians of hyperelliptic curves"

Since Bhargava and Shankar's new method of counting orbits, average orders of the 2,3,4,5-Selmer groups of elliptic curves over Q have been obtained. In this talk we will look at a construction of torsors of Jacobians of hyperelliptic curves using pencils of quadrics and see how they are used to compute the average order of the 2-Selmer groups of Jacobians of hyperelliptic curves over Q with a rational (non-)Weierstrass point.

Ian Payne, Pure Mathematics, University of Waterloo

"I Can't Get No (Constraint) Satisfaction"

Chun Kit Lai, McMaster University

"Fourier frames on general measure spaces"